1. Field of the Invention
This invention relates to a figure element revising method and, more particularly, to a figure element revising method for displaying and revising a group of figure elements including figure elements defined using figure elements that have already been defined.
2. Description of the Prior Art
In an automatic programming system for creating NC data using an automatic programming language such as APT or FAPT,
(a) a part program based on the automatic programming language is created by defining points, straight lines and circular arcs using simple symbols (this is referred to as "figure definition"), and then defining a tool path using the defined points, straight lines and circular arcs (referred to as "motion statement definition"), and
(b) the part program based on the automatic programming language is subsequently converted into NC data comprising NC data (EIA codes or ISO codes) in a format capable of being executed by an NC unit.
FIG. 6 is a view for describing figure definition statements. Figure definition of circles C.sub.1, C.sub.2, C.sub.3, C.sub.4 and straight lines S.sub.1, S.sub.2 is performed as follows using a keyboard or tablet: EQU C.sub.1 =x.sub.1, y.sub.1, r.sub.1 (1) EQU S.sub.1 =P(x.sub.2,y.sub.n2), P(x.sub.3,y.sub.3) (2) EQU C.sub.2 =S.sub.1, C.sub.1, r.sub.4, B, I, R (3) EQU C.sub.3 =x.sub.5, y.sub.5, r.sub.5 (4) EQU C.sub.4 =S.sub.1, C.sub.1, C.sub.2, B, I, O, L (5) EQU S.sub.2 =C.sub.2, C.sub.3, A, A (6)
In the foregoing,
equation (1) signifies a circle C.sub.1 of center (x.sub.1,y.sub.1) and radius r.sub.1 ;
equation (2) signifies a straight line S.sub.1 passing through two points (x.sub.2,y.sub.2), (x.sub.3,y.sub.3);
equation (3) signifies a circle C.sub.2 of radius r.sub.4 tangent to the straight line S.sub.1 from below, internally tangent to the circle C.sub.1 and located on the right side;
equation (4) signifies a circle C.sub.3 of center (x.sub.5,y.sub.5) and radius r.sub.5 ;
equation (5) signifies a circle C.sub.4 tangent to the straight line S.sub.1 from below, internally tangent to the circle C.sub.1, externally tangent to the circle C.sub.2 and located on the left side; and
equation (6) signifies a straight line (tangent) S.sub.2 tangent to the circle C.sub.2 from above and to the circle C.sub.3 from above. The alphabetic character A represents a qualifier meaning "above", B a qualifier meaning "below", R a qualifier meaning "right", L a qualifier meaning "L", I a qualifier meaning "internally tangent", and O a qualifier meaning "externally tangent".
As described in the example of the figure definition statement of the prior-art set forth above, there are two methods of figure definition. A first definition method entails defining points, straight lines and circles using absolute numeric data. A point is defined as EQU P=x, y
using the coordinates (x,y) of the point [see FIG.
7(a)]; a straight line is defined as EQU S=P(x.sub.1,y.sub.1), P(x.sub.2,y.sub.2)
using the two points (x.sub.1,y.sub.1), (x.sub.2,y.sub.2) through which the straight line passes [see FIG. 7(b)]; and a circle is defined as EQU C=x, y, r
using the coordinates (x,y) of the center of the circle and the radius r of the circle [see FIG. 7(c)]. A figure definition statement based on the first definition method shall be referred to as a first definition statement hereinafter.
The second definition method entails defining straight lines and circles using other points, straight lines and circles that have already been defined. For example, point P.sub.1 [see FIG. 7(d)] is defined as follows: EQU P.sub.1 =S, C, L
The straight lines S.sub.1 [see FIG. 7(e)] is defined as follows, by way of example: EQU S.sub.1 =C.sub.1, C.sub.2, A, A
(A is a qualifier meaning "above"); and the circle C [see FIG. 7(f)] is as follows, by way of example: EQU C=S.sub.1, S.sub.2, S.sub.3, R, A, L
A figure definition statement based on the second definition method shall be referred to as a second definition statement, hereinafter various types of second definition statements are available, that is, they are not limited to the foregoing examples.
When figure definition is performed, the arrangement is such that a figure element is defined by the first definition statement, and another figure element is defined by the second definition statement using the figure element in accordance with the first definition statement.
There are cases where it is desired to modify a figure element (FIG. 6), such as the circle C.sub.2, defined using an already defined figure element. In such case, the definition statement of circle C.sub.2 is EQU C.sub.2 =S.sub.1, C.sub.1, r.sub.4, B, I, R
Since definition is performed utilizing the figure elements S.sub.1, C.sub.1 based on the first definition statement, the figure elements S.sub.1, C.sub.1 and the radius r.sub.4 must be revised in order to make the modification. However, the figure definition statement of each figure element is not displayed on the display screen, and there is no correspondence between the symbols (P.sub.i, S.sub.i, C.sub.i) of the figures used by the figure definition statements and the figure elements painted on the display screen. Consequently, searching for figure elements and data utilized in the definition of the figure element desired to be modified is a troublesome operation, and making the revision is very difficult.
Accordingly, an object of the present invention is to provide a figure element revising method through which figure elements and data necessary for making a revision can be distinguished merely by designating the figure element desired to be modified, as a result of which revision of the figure element can be performed quickly and easily.